120 Volt Hardwire with a 9 volt Battery Back up feature(battery included).
Alarm-Pause.
Interconnectable up to 18 units.
Alarm an Power test feature and LED's.
Low battery warning.
10 Year Limited Warranty (battery excluded).
   |
| Features |
| Ionization Sensor |
| I 120V AC; Interconnectable |
| Battery back-up |
| Latching Alarm Indicator |
| Smart Technology |
| Single Button Test/Silence |
| Perfect Mount System |
| Mounting bracket lock |
| Battery Drawer lock |
| Battery pull tab |
| Side load battery drawer |
| Dust Cover |
| 9V Battery Included |
| 10-Year Limited Warranty |
BRK 4120 Series to 9120 Series Cross Reference Chart
| Old Model No. | New Model No. | Description |
| 4120 | 9120 | AC BRK Smoke |
| 4120-12ST | 9120-12ST | AC BRK Smoke in 12-pack Stadium Tray |
| 4120 | 9120 | AC BRK Smoke |
| 4120AB | 9120AB | AC/DC BRK Smoke w/Alkaline Battery |
| 4120B | 9120B | AC/DC BRK Smoke (includes silence) |
| 4120B-48B | 9120B-48B | AC/DC BRK Smoke 48 bulk pack |
| 4120B-48P | 9120B-48P | AC/DC BRK Smoke 48 pack |
| 4120B-GFD | 9120B-GFD | AC/DC BRK Smoke Gravity Feed Display |
| 4120LB | 9120LB | AC/DC BRK Smoke w/Lithium Battery |
| 4120SAB | Obsolete | Not needed-Silence is a standard feature |
| 4120SB | Obsolete | Not needed-Silence is a standard feature |
| 4120SB-12ST | 9120B-12ST | AC/DC BRK Smoke 12 pack Stadium Tray |
| 4120SB2 | Obsolete | AC/DC BRK Smoke 2 pack-Retail |
| 4120SB-48B | Obsolete | Not needed-Silence is a standard feature |
| 41206CP | 91206CP | AC BRK Smoke Contractor bulk 6-pack |
| 4120SB6CP | 9120B6CP | AC/DC BRK Smoke Contractor bulk 6-pack |
| 4120SB-GFD | Obsolete | Not needed-Silence is a standard feature |
| 4919A | 9120A | AC BRK Smoke Canada |
| 8120BL | Obsolete | Not needed. Latching is a standard feature. |
| SA4120B-48B | SA9120B-48B | AC/DC First Alert Smoke 48 bulk pack |
| SA4120CN | Obsolete | AC First Alert Smoke-clamshell |
| SA4121B-48B | Obsolete | Not needed-Silence is a standard feature |
| SA4121CN | SA9121CN | AC/DC First Alert Smoke-clamshell 3-pack |
| SC6120B | SC9120B | AC/DC BRK Smoke/CO combo |
| None | SC9120B-GFD | AC/DC BRK Smoke/CO Gravity Feed Display |
| None | SC9120BA | AC/DC BRK Smoke/CO combo-Canada |
| SC6120B-12ST | SC9120B-12ST | AC/DC BRK Smoke/CO combo-12-pack stadium tray |
| SA4121CN3 | Obsolete | Replaced by SA9121CN |